A Feast for the Senses

At Kitchen Theory, the chef Jozef Youssef practices “multisensory gastronomy” with the help of psychologists.

Photograph Courtesy Philip Wolmuth

Two years ago, an incensed group of Brits drew up a petition to address a matter that some deemed an act of “cultural vandalism”: the recipe for Cadbury Dairy Milk bars had changed. The new chocolate tasted “sweeter,” “sickly,” and “artificial,” irate candy lovers ranted online. An award-winning London chocolatier even weighed in, pronouncing the latest Dairy Milk formula to be “slightly nuttier” than its “milkier” antecedent. In fact, only the shape of the bar had been altered, its sharp corners and grid of squares rounded off to form a single column of chocolate with curved edges. This had, for some, completely transformed the flavor.

The Cadbury confusion involved two of the five senses, and confirmed the long-held wisdom that we “eat with our eyes.” But, as it turns out, our noses, ears, and fingers are crucial to the act of savoring, too. The technical term for this—the interplay between the senses—is crossmodal perception. Cadbury triggered it by accident, but a wave of chefs who champion what is known as “multisensory gastronomy” are exploiting it with ambitious intention. On three evenings each week through June, sixteen hungry people will file into Kitchen Theory, an “experimental kitchen” and pop-up restaurant in London, for a hundred-dollar tasting menu prepared by the chef Jozef Youssef, of the restaurants Fat Duck and Connaught, and the author of "Molecular Gastronomy at Home."

What sets this apart from any other hundred-dollar tasting menu is the identity of Youssef’s kitchen collaborators: a team of Oxford University psychologists, as well as experts in synesthesia, a rare condition in which the stimulation one sense sparks a vivid response in another, from the American Synesthesia Association and George Washington University. If molecular gastronomy tends to play with diners’ concept of food—Ferran Adrià has served “quail eggs” made of passion fruit and lemongrass, while Grant Achatz makes edible balloons—multi-sensory gastronomy takes it one step further, by shaking up how eaters understand their perception of the world. “You usually get a couple of screams in the room,” said Youssef’s wife, Lulu, who hosts the dinner each evening. More than a gastronomic gimmick, these meals illuminate a key truth about the mind: the senses do not work in isolation but in concert.

Lulu guides guests to a long row of tables in a white, Swedish-modern-style room bathed in the soft glow of L.E.D. lanterns and the light from a projector. The meal begins with a video explaining the human propensity to assign colors to each of the basic tastes, after which diners are presented with an amuse bouche and a challenge: guess which of the four differently colored spheres, each served on its own transparent spoon, is salty, sweet, bitter, and sour by using hue alone. The red sphere releases a liquid burst of sweet cranberry and rose; the green a sour lime mixture; the white a salty Indian raita; and the black a bitter rush of chocolate and Guinness.

Next comes a dish called Bouba & Kiki, inspired by a nonsense phrase made famous by the psychologist Wolfgang Köhler’s 1929 study, “Gestalt Psychology,” which showed that we have a tendency to match sounds with shapes; “kiki,” for example, is angular. Subsequent research has shown that we associate sounds with flavors, too: presented with a set of options, subjects rated mint chocolate and cheddar cheese as more “kiki,” but chocolate mousse and brie as more “bouba.”

At Kitchen Theory, the Bouba & Kiki arrives on a plate that has been sawed in two. One half holds sweet potato spheres on a bed of red and white dots made from paprika and cheese; the other offers pointy shards of raw sea bass next to ground yellow corn shaped into powdered squares. Diners are told to “start with the bouba,” and again, it’s up to them to guess which one that is. Like subjects being tested in university labs, most start with the round food.

Another dish—grilled paneer cheese served with pickled enoki mushrooms, bulghur wheat, and bacon—comes with textured cubes instead of condiments. By alternately stroking rough, fuzzy, and gritty surfaces as they chew, diners find that the mouth-feel of what they’re eating morphs. At one of the dinners this spring, a well-dressed woman in her seventies grew agitated when she touched a cube’s sandpaper face. It made the crunch of bulgur wheat unbearable. “She had to keep her fingers running over the velvet side to finish the dish because she found it so much more pleasant,” Youssef recalled.

During a course of poached langoustine velouté, Lulu sprays the scent of saffron into the air, to illustrate how flavor is built through the nose and not just the taste buds. (Another course is seasoned with a bacon perfume.) The playlist for the evening features “music pairings,” including Amon Tobin’s “Piece of Paper,” an electronic composition that evokes metal hand mixers clanging against stainless-steel bowls, which Youssef uses to enhance the crackling of the Pop Rocks-like candy in the dessert. According to Helen Bagnall, an early Kitchen Theory guest, this all makes for a spectacular meal. “I was incredibly aware of every flavor, every mouthful of that food on lots of different levels and lots of senses, and that really heightened my pleasure,” she said.

Youssef’s de facto sous chef is Charles Spence, an experimental psychologist and the head of Oxford’s Crossmodal Research Laboratory. Spence has spent his career trying to show how flavor is, as he sees it, “one of the most multi-sensory experiences we have.” The night before we spoke, he’d asked a group of professional food developers to eat jellybeans with clothespins clipped to their noses, in order to illustrate how dependent what we think of as “taste” is on smell. “Whenever we have a flavor experience, it is constructed by the mind, on the basis of the cues in the food itself, but also all those cues around it—the lighting, the music, the chair we’re sitting on,” he told me. “You can’t ignore it. You can try to, but it is there. Always.” Youssef—who first met Spence five years ago, and quotes his papers as if they were recipes—used Oxford studies as a basis for brainstorming the tasting menu, which he then refined through conversations with Spence, Spence’s colleagues, and synesthesia experts in the United States. Youssef is a frequent visitor to Spence’s lab, and Spence, in turn, is now using the chef’s amuse bouche in a follow-up study that looks at how consistently subjects can intuit the flavor of the spoon’s sphere from its color. (They get it right about eighty-five per cent of the time, Spence told me.)

Spence and others have demonstrated that flavor is not only influenced by surrounding stimuli—the weight of the silverware, the hum of a noisy room—but that these outside cues can direct our experiences in specific, predictable, and measurable ways. A recent study found that a piece of toffee could be made to taste either sweeter or more bitter depending on whether it was eaten while listening to a “sweet” tune (featuring high-pitched piano notes) or a “bitter” melody (a low-pitched soundtrack heavy on bass and trombone). In another study, published last November in the journal Flavour, subjects tasted wine in rooms bathed in green-, red- or white-colored lights, with “sweet” or “sour” sounds piped in. The same glass of Rioja tasted significantly “fresher” under green illumination with staccato “sour” music, while the wine took on fruitier aromas in the red-hued room filled with the legato “sweet” melodies. Scientists have uncovered so many sensory overlaps—between flavor and sound, sound and smell, smell and sight, sight and touch—that, Spence has written, it “appears likely that crossmodal correspondences exist between all possible pairings of sensory modalities.”

Some psychologists and neuroscientists see the correspondence between the senses as a weaker form of synesthesia. (Synesthetes say that they can smell musical chords, or taste meat when wool brushes against their skin.) Daphne Maurer, a professor of psychology at McMaster University, in Hamilton, Ontario, is in this camp. She argues that crossmodal perception originates in the “sensual bouillabaisse” from which we emerge as infants—that we are all, at least as babies, synesthetes. In newborns, regions of the brain that will later specialize in a single sensory modality are still linked. This jumble of synaptic connections mixes feelings, shapes, sounds, and aromas into a stew of sensory stimuli, producing a situation in which caresses could have smells. “The wildest of 1960s psychedelia could not begin to compare with the everyday experience of a baby's entry into the world,” Maurer wrote in "The World of the Newborn," which she co-authored with her husband, the science writer Charles Maurer, in 1988. Over time, a child’s environment reinforces connections between certain stimuli and specific regions of the brain, eliminating the superfluous pathways to create cortical areas that specialize in processing a single sense. Multisensory perception remains as the dregs of that sensory soup.

The “neonatal synesthete” hypothesis could help explain why crossmodal perception seems to be universal. Maurer has documented the so-called “Bouba-Kiki effect” in children as young as two-and-a-half: they match rounder shapes with nonsense words that have rounded vowels. Another recent study looked at the members of the Himba, a remote, semi-nomadic tribe in Namibia that has no written language and little interaction with Westerners. They, too, associated the word “bouba” with certain shapes, and “kiki” with others. Yet the Himba’s “bouba” and “kiki” flavor associations were directly opposed to those of European subjects. This points to another potential explanation for our multimodal minds: experience. Spence, who argues that the neonatal-synesthete theory is “speculative” and “hard-to-pin down,” maintains ,along with several of his colleagues at Oxford, that our multisensory correspondences are learned and influenced by our surroundings. Years of eating apples, cherries, limes, and lettuce train us to expect that red foods will be sweet, while green foods will be sour or bitte**r.**** **Stimuli in our inedible environments—anything from the sight of chartreuse dinner plates to the sound of hard-rock music—can cue up expectations and subconscious associations that filter what we perceive as we eat and drink.

The growing body of research on multisensory perception has inspired chefs like Youssef to reconsider everything from napkins to wallpaper. The Michelin-star chef Heston Blumenthal, who has used audio of crashing waves to amp up flavor in an oyster dish, was an early multisensory gastronomy pioneer (though the Italian futurist Filippo Tommaso Marinetti, who published "The Futurist Cookbook," in 1932, actually beat him by several decades). Now there are immersive dining experiences at Ultraviolet, in China, and El Celler de Can Roca, in Spain, and a sonic wine bar in New Zealand. British Airways has even introduced “Sonic Seasoning,” a playlist that attempts to make bland airplane food more flavorful. They suggest livening up the taste of their in-flight dessert with Otis Redding’s “The Dock of the Bay” because “low tones can bring out the bitterness in chocolate.” Some flavor, it seems, is better than no flavor at all.

The catchy “multisensory gastronomy” moniker ultimately describes a process of sensory manipulation. In some cases, these sleights-of-hand could save us from ourselves. Companies or chefs could cut fat but not flavor by simply altering the way food is served. Those Dairy Milk bars that some perceived as sweeter, despite the fact that the recipe had not been altered, might prove a perfect test case for healthier junk food: perhaps if Cadbury had actually cut down on the sugar when they changed the shape, to compensate, the bar would have tasted the same as ever. Playing with crossmodal perception might even prove a boon for the planet. Youssef dreams of substituting beef with a more eco-friendly form of protein. “Through our understanding of multisensory dining,” he told me, “maybe we can augment these things like crickets and insects.” You may one day steel yourself for Kiki Cricket, served on a square plate to bring out the crunch, and with a textured cube, just in case. But even if multisensory gastronomy fails to save the world, at the very least it could rescue your next dinner party. Over-salt the salad? Just cue up some sour songs. A little Debussy could be delicious.

Bianca Bosker is the author of “Cork Dork,” published by Penguin Books.

By deconstructing the ways in which sensory inputs are combined by the brain, scientists can begin to understand the feeling of being a body in the world.

The mad genius of “Modernist Cuisine.”

As the years passed, Tom grew more entrenched in his homelessness. He was absorbed in lofty fantasies and private missions, aware of the basest necessities and the most transcendent abstractions, and almost nothing in between.